Yeah I figured as much....
I myself have rage quit here a few different times myself. Keep coming back whenver I get a graveyard shift job though....
Alternative solution to that, (more work than needed disclaimer) is make it an optional setting for managers to choose to do it that way that they can change end of seasons (after contract stuff is done) each year if they want. Those players then sold under those pretense would stay as they were regardless of new team's setting until the next cycle date where it would have changed for them anyways.
But as I stated. Way more work than needed...
Better solution than that would be have a "trial run country" where its like that (players cannot be traded to teams not in that country) and do it that way. Similar-ish to when utopia first started up.